codex-lv4-may-2025

Server Mini-Project: CRUD API in Memory

Build a RESTful Express API that implements core CRUD operations using in-memory data storage. This project consolidates everything you’ve learned about Express routes, HTTP status codes, JSON responses, and error handling.

Focus on just ONE resource for this project—choose something you’re interested in like cats, baseball-cards, videos, or any other single collection. This keeps the scope manageable while you master the fundamentals.

📚 Instructions

📖 Start Here: Review the server lesson guides (Parts 1-5) to understand Express fundamentals, route handling, and testing patterns.

⚠️ Important: Please change “items” to a resource of your choosing throughout this project. Examples: cats, baseball-cards, videos, books, pokemon, or any other collection you’re interested in. This makes your API more personal and helps you think about real-world use cases.

Additional Resources:

✅ Requirements

Your Express API must include:

Core CRUD Operations
- GET /items - Return all items (status 200)
- POST /items - Create a new item (status 201)
- GET /items/:id OR DELETE /items/:id - Retrieve or remove a specific item
- Proper JSON responses for all endpoints
- Note: Replace “items” with your chosen resource name (e.g., /cats, /baseball-cards, /videos)
Error Handling
- Return 404 with JSON error body when item not found: { "error": "message" }
- Return 400 with JSON error body for invalid input
- Consistent error response format across all endpoints
Data Management
- Use in-memory array to store items
- Generate unique IDs for each item (use crypto.randomUUID())
- Seed initial data with at least 2-3 sample items
Code Organization
- Export Express app for testing
- Clean, readable code structure
- Meaningful variable and function names
- Comments explaining key sections
Testing (Optional but Recommended)
- Set up Vitest with Supertest
- Write at least 3 test cases covering happy paths and error cases
- Run tests with npm run test
Documentation
- README.md with setup instructions
- Description of endpoints and their behaviors
- Example requests/responses
- List of technologies used

🎓 Deliverable

Submit: GitHub repository URL containing:

All source code organized in proper structure
Express app with CRUD routes
package.json with dependencies
README.md with:
- Project description
- Setup instructions (npm install, npm run dev)
- API endpoint documentation
- Example requests using Postman or cURL
- Testing instructions (if tests included)
Clear Git commit history (commit after each milestone)

Before submitting, verify:

App runs with npm run dev without errors
All required CRUD operations implemented
Status codes are appropriate (200, 201, 400, 404)
Error responses use consistent JSON format
README is complete with all sections
Code is clean and commented
Tests pass (if included)

📝 Project Phases

Phase 1: Setup & Basic Routes

Initialize Express project
Set up express.json() middleware
Choose your resource name (e.g., cats, baseball-cards, videos) and replace “items” throughout
Create in-memory data array with seed data
Implement GET /items route

Key Terms

API (Application Programming Interface) - A set of rules that lets software systems communicate
Express server - A Node.js framework for building APIs and backend routes
Local host (localhost) - Your own computer acting as a server
Port - A numbered communication channel your server listens on
index.js (Main script) - The main entry file for a Node.js or Express app
Module type (module vs commonjs) - Two ways Node organizes files
JSON (JavaScript Object Notation) - A lightweight data format for sending structured data
GET (Method) - Used to request data from the server

Phase 2: Create Operation

Implement POST /items route
Add validation for required fields
Generate unique IDs for new items
Return 201 status with created item

Key Terms

POST (Method) - Used to send data to the server (creating something new)
Body - The data sent in an HTTP request or response (usually JSON for APIs)
Middleware - Functions in an Express server that run before your route handler
Content type (MIME type) - A header describing what kind of data is being sent

Phase 3: Read/Delete by ID

Choose either GET /items/:id or DELETE /items/:id
Implement route parameter handling
Add 404 error handling for missing items
Return appropriate status codes

Key Terms

Request - The message the client sends to the server
Response - The message the server sends back to the client
Status codes (200, 404, 500, etc.) - Numbers describing the result of a request

Phase 4: Error Handling & Polish

Centralize error responses
Add validation for POST requests
Test all endpoints with Postman
Write README documentation

Key Terms

HTTP Headers - Extra information added to a request or response
Request headers - Small pieces of metadata the client sends with a request
Response headers - Metadata sent back with a response

Phase 5: Testing (Optional)

Set up Vitest and Supertest
Write tests for each endpoint
Test both success and error cases
Run coverage report

🆘 Need Help?

Review the server lesson guides (Parts 1-5)
Check Express documentation for route examples
Use Postman to test your endpoints
Use console.log() to debug request/response data
Post questions in the discussion forum

📊 Rubric (100 pts)

Chosen operations work (0-25 pts)
- All implemented routes function correctly
- Data persists during server session
- IDs are generated and used properly
Errors and statuses consistent (0-25 pts)
- Correct HTTP status codes (200, 201, 400, 404)
- Consistent JSON error format
- Appropriate error messages
Project runs from README (0-25 pts)
- Clear setup instructions
- Dependencies install correctly
- Server starts without errors
Code organization (0-25 pts)
- Clean, readable code structure
- Proper use of Express patterns
- Meaningful naming conventions
- Helpful comments

Good luck building your API! 🚀✨

This mini-project consolidates concepts from Week 1 server lessons and prepares you for database integration in future weeks.